On Sunday 27 January 2008 20:49:42 Anne Wilson wrote:

On Sunday 27 January 2008 15:41:04 Marc Perkel wrote:

...

Strange problem and I'm not sure what's causing it. I'm using IMAP. A new message arives in the inbox. I see it displayed in the message list in bold. I click on the message and it looks like it's reading it by the previous message that was in the window remains and the new message is still bold (unread). However I can then click on an old message and then click on the new message again and it reads.

I have reported the same behaviour in KMail over Dovecot - and someone else also reported it. That seems to suggest that it's a Dovecot problem.

I should have said that I reported it on the kde-pim list, as I thought it was a Konntact problem. I classed it as a minor annoyance, and didn't follow it up when no-one seemed to know why it was happening.

Anne

Marc Perkel wrote:

OK - I didn't know that I might be reporting something new. Here's some more details. I leave my computer on at might (Windows XP) and it's worse in the morning when I wake up. Thunderbird's checks the email every 1 minute and it's set up to check several IMAP folders. I'm running the latest Thunderbird release as will as the latest Dovecot (not the beta versions).

In the morning it is as if it can't access dovecot at all. I get an hour glass as if it is waiting for something that's never going to respond. But if I shut down Thunderbird and restart it then everything works normal for a while.

A summary of below: make sure you are actually still connected to your original session in dovecot before you suspect it:

Try running a script to run 'netstat' frequently, say once a minute, and log the port numbers from the connection, example: TCP reinheitsgebot:3482 mail.egr.msu.edu:993 ESTABLISHED TCP reinheitsgebot:3485 mail.egr.msu.edu:993 ESTABLISHED

You probably want to do this on the server side as well as the client side, just to check that if a connection is dropped, it happens on both at the same time (if not, something sounds odd!).
I'm not sure if your problem happens if you only have thunderbird check the inbox, but I would expect at least one connection (inbox) to stay connected constantly without disruption. If the client side port number changes (eg. 3482), it got disconnected for some reason. For the most part, Thunderbird tries to make disconnections invisible to the user, which is nice when it works right, but misleading when something goes wrong, such as when thunderbird acts obstinant about loading messages but works when you restart.

The reason I suggest this, and even if it might be a simpler case for you but similar symptoms/effect, I had a load balancer situation where connections would get dropped on the client side from a cause outside of the load balancer or server, and thunderbird would not always reconnect nicely when that happened.
Literally the fault was not in the load balancer or server, but another server that stuck its nose in and effectively tried to steal the connection, making the client run into a brick wall and disconnect. The same happened to https connections.

You might also try a different client such as mutt, which will make it painfully obvious if you get disconnected overnight, because it won't try to reconnect.

Now on the other hand, if you can verify a single connection does stay open using the same source/dst port pair, you could start zeroing in on what is actually happening inside that connection, if it takes tcpdump on both side plus nonssl imap, etc.